If you're using FC3 or FC4 you've got udev so you'll need to edit the rules to set the group when the device file is created.
Look in /etc/udev/rules.d/50-udev.rules and you will see the line which controls /dev/dsp :
You should be able to change the default group ownership like this:
KERNEL="dsp0", SYMLINK="dsp" , GROUP="audio"
Make sure you back up the rules file first (probably to a sepparate directory so udev doesn't try to read both).
I'm sure that instead of altering 50.udev.rules you should create a local rules file but the above should work. If yum or up2date updates udev then I think you may
loose the changes.
See man udev for more info.
Hope that helps